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Effect of acute hypoxia on ATP-sensitive potassium current in ventricular myocytes of guinea-pig

Pan Shengjun, Zhou Zhaonian

Shanghai Institute of Physiology, Chinese Academy of Sciences.Shanghai 200031

Abstract

The role of the ATP-sensitive potassium channel in arrhythmogenesis is not clearly understood. Cellular K~(+) loss and accumulation of [K~(+)]_(0) may contribute to genesis of malignant ventricular arrhythmia during myocardial ischemia. In the present study, acute hypoxia simply caused a partial decrease in K~(+) efflux at normal [K~(+)]_(0),which was not sensitive to glibenclamide (5×10~(-3) mmol/L). However, at a higher concentration of [K~(+)]_(0) (10.8 mmol/L), the outward K~(+) current increased dramatically after 10 min hypoxia, which was accompanied with an irreversible hypercontracture and eventual death of the cell. The I-V relation was liner with increasing repolarization,which was blocked by glibenclamide, an antagonist of ATP-sensitive potassium channel. The results suggest that the increased K~(+) current is ATP-sensitive and is facilitated by accumulation of the [K~(+)]_(0).

Key words: Hypoxia;ATP-sensitive potassium channel;High K~(+)

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Citing This Article：

Pan Shengjun, Zhou Zhaonian. Effect of acute hypoxia on ATP-sensitive potassium current in ventricular myocytes of guinea-pig. Acta Physiol Sin 1997; 49 (1): (in Chinese with English abstract).